Conventionally, there has been known an image recording apparatus provided with a cartridge in which ink is stored, a sub tank connected to a recording head, and a liquid flow passage and a gas flow passage which connects the cartridge and the sub tank. The cartridge is disposed vertically above the sub tank. The liquid flow passage and the gas flow passage connect the cartridge and the sub tank in the vertical direction. The liquid flow passage and the gas flow passage are opened to the lower surface of the cartridge and the upper surface of the sub tank, respectively. Further, an air introduction opening is provided on an upper wall of the sub tank such that the air introduction opening penetrates the upper wall, and gas is supplied to the gas flow passage from the air introduction opening through the inside of the sub tank.